Peristaltic Pump - Patent 7625189

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Peristaltic Pump - Patent 7625189 Powered By Docstoc
					


United States Patent: 7625189


































 
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	United States Patent 
	7,625,189



 Cheng
 

 
December 1, 2009




Peristaltic pump



Abstract

A peristaltic pump, for propelling liquid through a flexible pump tube,
     includes an outer casing having a guiding channel wherein an operating
     portion of the pump tube extends along the guiding channel. The
     peristaltic pump further includes at least two pressuring rollers
     supported at the outer casing in a radially movable manner which can move
     outwardly to press against the operating portion of the pump tube. A
     center driving mechanism is supported at a center portion of the outer
     casing to radially push the pressure rollers and to drive the pressuring
     rollers to concurrently rotate such that the pressuring rollers roll
     against the operating portion of the pump tube for continuously
     propelling the fluid in the pump tube in the direction of rotation.


 
Inventors: 
 Cheng; Zaijun (Shenzhen, Guangdong province, CN) 
Appl. No.:
                    
10/592,104
  
Filed:
                      
  March 9, 2005
  
PCT Filed:
  
    March 09, 2005

  
PCT No.:
  
    PCT/CN2005/000288

   
371(c)(1),(2),(4) Date:
   
     September 07, 2006
  
      
PCT Pub. No.: 
      
      
      WO2005/085640
 
      
     
PCT Pub. Date: 
                         
     
     September 15, 2005
     


Foreign Application Priority Data   
 

Mar 10, 2004
[CN]
2004 1 0008362



 



  
Current U.S. Class:
  417/474  ; 417/476; 417/477.1; 417/477.3; 417/477.7; 417/477.8
  
Current International Class: 
  F04B 43/08&nbsp(20060101); F04B 43/12&nbsp(20060101); F04B 45/06&nbsp(20060101)
  
Field of Search: 
  
  





 417/474,476,477.1,477.3,477.7,477.8
  

References Cited  [Referenced By]
U.S. Patent Documents
 
 
 
3723030
March 1973
Gelfand

5630711
May 1997
Luedtke et al.

6641249
November 2003
Miyauchi

6733255
May 2004
Ota et al.



   Primary Examiner: Kramer; Devon C


  Assistant Examiner: Bobish; Christopher


  Attorney, Agent or Firm: Chan; Raymond Y.
David and Raymond Patent Firm



Claims  

What is claimed is:

 1.  A peristaltic pump for propelling liquid, comprising: an outer casing having a guiding channel and defining a circular path therealong;  a flexible pump tube, which is
adapted for allowing said liquid flowing therealong, having an operating portion extended along said guiding channel of said outer casing;  a driving shaft;  at least two pressuring rollers spacedly and eccentrically supported at said outer casing in a
radially movable manner for rotatably moving along said circular path, wherein said two pressuring rollers are arranged to radially and outwardly moved to press against said operating portion of said pump tube along said circular path;  and a
transmission unit, which comprises at least first through fifth driving plates mechanically communicated with said driving shaft in a side-by-side manner, wherein each of said driving plates has at least one peripheral indention formed thereon, and a
pedal slot having a predetermined arc length formed in a central portion of said corresponding driving plate for connecting with said driving shaft, wherein said peripheral indention of said driving plate has a predetermined depth for at least partially
receiving said pressuring roller therein, wherein when said driving shaft is driven to rotate, said driving plates are arranged to rotate sequentially for sequentially engaging with and disengaging from said pressing rollers by said corresponding
peripheral indention, so as to allow said pressing rollers to be sequentially biased in a radial direction for biasing against a corresponding portion of said flexible pump tube, wherein said third driving plate is sandwiched between said second and said
fourth driving plates, wherein said arc length of said pedal slot of each of said second and said fourth driving plates is larger than said arc length of said pedal slot of said third driving plate, wherein said pressuring rollers are sequentially driven
to bias against different portions of said flexible pump tube when said driving shaft rotates, so as to maximize an efficiency and effectiveness of pumping said liquid while minimizing normal wear and tear of said flexible pump tube.


 2.  The peristaltic pump, as recited in claim 1, wherein said second, said third and said fourth driving plates are sandwiched between said first and said fifth driving plate, wherein said arc length of said pedal slot of each of said first and
said fifth driving plates is larger than said arc length of said pedal slot of each of said second and said fourth driving plates.


 3.  The peristaltic pump, as recited in claim 1, wherein at least two of said pressuring rollers are symmetrically and planetary supported at said outer casing in a radially movable manner.


 4.  The peristaltic pump, as recited in claim 2, wherein at least two of said pressuring rollers are symmetrically and planetary supported at said outer casing in a radially movable manner.


 5.  The peristaltic pump, as recited in claim 1, further comprising a retainer retaining a radial movement of said pressuring rollers, wherein said retainer further has a retainer rod and a retainer slot to further stabilize said pressuring
roller.


 6.  The peristaltic pump, as recited in claim 2, further comprising a retainer retaining a radial movement of said pressuring rollers, wherein said retainer further has a retainer rod and a retainer slot to further stabilize said pressuring
roller.


 7.  The peristaltic pump, as recited in claim 4, further comprising a retainer retaining a radial movement of said pressuring rollers, wherein said retainer further has a retainer rod and a retainer slot to further stabilize said pressuring
roller.


 8.  The peristaltic pump, as recited in claim 1, wherein a corner of said peripheral indention of each of said driving plates is a smooth corner which tangents out with an outer diameter of said corresponding driving plate.


 9.  The peristaltic pump, as recited in claim 4, wherein a corner of said peripheral indention of each of said driving plate is a smooth corner which tangents out with an outer diameter of said corresponding driving plate.


 10.  The peristaltic pump, as recited in claim 7, wherein a corner of said peripheral indention of each of said driving plate is a smooth corner which tangents out with an outer diameter of said corresponding driving plate.


 11.  The peristaltic pump, as recited in claim 4, wherein a thickness of said combined driving plates is approximately equal to a width of said pressuring roller, and is approximately equal to two times of a width of said compressed pump tube.


 12.  The peristaltic pump, as recited in claim 7, wherein a thickness of said combined driving plates is approximately equal to a width of said pressuring roller, and is approximately equal to two times of a width of said compressed pump tube.


 13.  The peristaltic pump, as recited in claim 10, wherein a thickness of said combined driving plates is approximately equal to a width of said pressuring roller, and is approximately equal to two times of a width of said compressed pump tube.


 14.  The peristaltic pump, as recited in claim 7, wherein said peripheral indention of each of said driving plates is located at a circumference edge of said driving plate and said peripheral indention provides a space for said pressuring roller
to receive in and has a depth approximately equal to a distance that said compressed pump tube needs to recover from.


 15.  The peristaltic pump, as recited in claim 10, wherein said peripheral indention of each of said driving plates is located at a circumference edge of said driving plate and said peripheral indention provides a space for said pressuring
roller to receive in and has a depth approximately equal to a distance that said compressed pump tube needs to recover from.


 16.  The peristaltic pump, as recited in claim 13, wherein said peripheral indention of each of said driving plates is located at a circumference edge of said driving plate and said peripheral indention provides a space for said pressuring
roller to receive in and has a depth approximately equal to a distance that said compressed pump tube needs to recover from.  Description  

BACKGROUND OF THE PRESENT INVENTION


1.  Field of Invention


The present invention relates to a pump for propelling liquid through a flexible tube segment, and more particularly to a peristaltic pump for propelling liquid through the flexible tube in a concealed manner to ensure the purity of the liquid
during transmission and to prevent an environmental pollution of the peristaltic pump.


2.  Description of Related Arts


The peristaltic pump is commonly used as a safe and stable liquid pumping device in many different fields such as the medical, pharmaceutical, chemical, nuclear, aviation, and environmental industries.


Nowadays, conventional peristaltic pumps usually comprise an outer casing, a flexible pump tube which is adapted for allowing fluid to flow therealong, a plurality of rotating rollers spacedly supported at the outer casing at equal radial
distance.  The rotating rollers exert pressure on the pump tube thus to propel the liquid.  A negative pressure will then be formed when the pump tube returns to it normal position so ask to suck in fluid from the source and thus continuously propel the
fluid to travel in the pump tube.  There are many disadvantages for such a conventional peristaltic pump.  For examples, the peristaltic pump enclosed in China Patent CN85204827 and CN87107936 uses the rotating rollers to only exert pressure on the pump
tube in a particular arc section of the guiding channel so as to achieve a more convenient installation of the pump tube.  As a result, the design will experience a radial pulsing force on a particular section of the pump tube and also faces the
following problems that are hard to overcome:


1.  a high power motor is required to drive the machine to overcome the friction on the particular side, especially for the initial force and the torque, therefore it increases the size of the machine, i.e. the bigger size of driving shaft and
the power of the motor, and the design has a low efficiency;


2.  the machine is easy to wear out, a special design is needed to suit for the machine in order to keep a desired pressure and displacement exerted by the rollers on the pump tube; and


3.  the machine is noisy.


SUMMARY OF THE PRESENT INVENTION


The technical problem that the present invention seeks to solve is to provide a peristaltic pump that is accurate in pumping fluid, cost efficient, low manufactory cost, convenient to repair and minimize the noise level of the machine.


Accordingly, in order to solve the above technical problems, the present invention provides a peristaltic pump comprises an outer casing that has at least one guiding channel, at least one flexible pump tube installed inside the guiding channel,
at least two pressuring rollers which is driven by a center driving mechanism.  The pump tube has an operating portion and circulates the guiding channel more than one full circle.  The pressuring rollers are supported at the circular edge of the center
driving mechanism and are driven by the center driving mechanism to rotate and exert pressure on the operating portion of the pump tube thus pumping the fluid along the pump tube.


As an embodiment of the present invention, the center driving mechanism comprises a driving shaft capable of rotating to drive the pressuring rollers, a retainer which is used to retain and support the pressuring rollers, at least a driving plate
which can rotate as the same manner as the driving shaft, and a plurality of peripheral indentions formed on outer edges of the driving plates so that the pressuring rollers can be received at the peripheral indention.


According to the present invention, the retainer comprises at least one pedal.  A pedal slot is formed at one of the driving plates as a starting plate that the pedal is engaged with the pedal slot.  The center driving mechanism comprises at
least two driving plates including the starting plate, preferably three or above.  The number of the driving plates excluding the starting plate should preferably come in pairs so as to keep symmetry of the center driving mechanism.  Accordingly, the
center driving mechanism can be constructed to have a plurality set of driving plates that one set of the driving plates is formed as the starting plate.  The starting plate can be a single plate structure and should be positioned at the center between
other driving plates.  The thickness of the single starting plate could be double the thickness of the other driving plates.  The pedal slot of the starting plate matches the size of the pedal.  The pedal slots of the other driving plates extends along
it arc length which is adapted to be driven by the pedal in a predetermined order of the driving plates.  A corner of the peripheral indention of the starting plate can be formed in a roundness manner to the outer diameter by making the edge tangent to
the outer diameter such that the edge of the peripheral indention is smoothly and gradually extended from the bottom side of the peripheral indention to the outer edge of the starting plate.


In addition, the retainer is used to the distance between the pressuring rollers.  The retainer further comprises a retainer shaft protrudes out from two sides of the pressuring roller and engages within a retainer slot of the retainer so that
the pressuring roller can be supported firmly and its distance between the pump tube and the driving plates can be retained.


The total thickness of the driving plates should be equal to the length of the pressuring roller and is approximate two times the width of the compressed pump tube.  The peripheral indentions are equally spacedly installed at the outer edges of
the driving plates and have a corresponding pressuring roller to engage with.  The depth and shape of the aligned peripheral indentions of the driving plates should correspond to diameter size of the pump tube so that the pump tube is allowed to recover
to its original shape when the pressuring roller is engaged with the peripheral indention of the starting plate.


The outer casing of the peristaltic pump can comprise a plurality of guiding channel wherein each guiding channel has one single pump tube.  As an alternative, the outer casing of the peristaltic pump comprises only a single guiding channel but
capable to have multiple pump tubes installed within.


The advantage of the present invention is that the peristaltic pump has a full complete circle of propelling path for the pump tube to propel liquid.  Since it is a full circle and the pressuring rollers are evenly distributed all around, the
force of the pressuring rollers can couple with each other and thus minimize the problem of getting a single stressed area in the peristaltic pump.  The pressure exerted on the pump tube are also evenly distributed along the full circle thus to provide a
more accurate and stable propelling motion.  The present invention can minimize the noise as well as manufacturing and repairing cost of the peristaltic pump.  When the peristaltic pump is not in used, the pressuring rollers can receive in the peripheral
indention so that the pump tube will not be receiving unnecessary pressure.  And the design makes the installation and tuning of the pump tube easier and is suitable for various types of pump tubes.


A main object of the present invention is to provide a peristaltic pump for propelling liquid through a flexible tube segment which is very stable and accurate in propelling liquid while the noise from the peristaltic pump can be minimized.


Another object of the present invention is to provide a peristaltic pump for propelling liquid through a flexible tube segment which is very energy efficient.  Another object of the present invention is to provide a peristaltic pump for
propelling liquid through a flexible tube segment without exerting pressure on the tube when installing the tube into the peristaltic pump in the beginning of the operation so as to simplify the operation of peristaltic pump and to prevent pump tube
being aged when the pressure continuously exerts at the pump tube while being unused.


Another object of the present invention is to provide a peristaltic pump for propelling liquid through a flexible tube segment which does not involve complicated mechanical structure, so as to minimize the manufacturing and repairing cost of the
peristaltic pump.


Another object of the present invention is to provide a peristaltic pump for propelling liquid through a flexible tube segment which minimizes the noise effectively.


Accordingly, in order to accomplish the above objects, the present invention provides a peristaltic pump for propelling liquid through a flexible tube segment comprising:


an outer casing having a guiding channel and defining a circular path therealong;


a flexible pump tube, which is adapted for allowing the liquid flowing therealong, having an operating portion extending along the guiding channel of the outer casing;


at least two pressuring rollers spacedly and eccentrically supported at the outer casing in a radially movable manner; wherein the two pressuring rollers are radially and outwardly moved to press against the operating portion of the pump tube
along the circular path;


a center driving mechanism supported at a center portion of the outer casing to radially push the pressure rollers and to drive the pressuring rollers to concurrently rotate such that the pressuring rollers roll against the operating portion of
the pump tube for continuously propelling the fluid in the pump tube in the direction of rotation. 

BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 is a top sectional view of the peristaltic pump according to a preferred embodiment of the present invention.


FIG. 2 is a side sectional view of the peristaltic pump according to the above preferred embodiment of the present invention.


FIG. 3 is a front view of the driving plate of the transmission unit according to the above preferred embodiment of the present invention illustrating their peripheral indention and pedal slots.


FIG. 4 illustrates an alternative mode of the starting plate according to the above preferred embodiment of the present invention.


FIG. 5 illustrates a configuration of the present invention using two pump tubes.


FIG. 6 illustrates a configuration of the present invention using three pump tubes.


FIG. 7 illustrates another alternative of the present invention which the driving plate has two pedal slots.


FIG. 8 is a side view of the outer casing illustrating that it is divided into the upper layer and the lower layer and is capable of rotating for ease of tuning and installation.


DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT


Referring to FIG. 1 and FIG. 2 of the drawings, the peristaltic pump comprises an outer casing 10, a center driving mechanism, at least two pressuring rollers 40, a retainer 60, and a flexible pump tube 90.  The outer casing 10 has a guiding
channel 12 formed along an inner wall of the outer casing 10 and defines a circular path therealong, a center driving mechanism supported at a center portion of the outer casing 10.  There are pressuring rollers 40 spacedly and eccentrically supported at
the outer casing 10.  The retainer 60 is used to retain and support the pressuring roller 40.  The flexible pump tube 90 made of silicon, which is adapted for allowing the liquid flowing therealong, has an operating portion extending along the guiding
channel 12 of the outer casing 10.  Accordingly, the pressuring rollers 40 are symmetrically and planetary supported at the outer casing in a radially movable manner.  The center driving mechanism comprises a motor which drives a driving shaft 20.  A
transmission unit 30 comprises a cylindrical driving element, wherein a pedal 33 protrudes out from an outer surface of the driving element, and a plurality of driving plates 501, 502, 503, 504, and 505 in an overlapped manner.  According to the
preferred embodiment of the present invention, there are five driving plates 501-505.


Referring to FIG. 3 of the drawings of the preferred embodiment, the first to fifth driving plates 501-505 are very similar in a circular structure.  The third driving plate 503, which is also regarded as a middle starting plate, has three
peripheral indentions 5033 in an arc shape evenly formed at the circumferential edge of the third driving plate 503.  The center portion of the third driving plate 503 has a pedal slot 5035.  The third driving plate 503 has a predetermined diameter that
the third driving plate 503 is adapted to push the pressuring roller 40 to substantially press against the pump tube 90 within the guiding channel 12.  The depth and shape of the peripheral indention 5033 of the third driving plate 503 should correspond
to diameter size of the pump tube 90 so that the pump tube 90 is allowed to recover to its original shape when the pressuring roller 40 is engaged with the peripheral indention 5033 of the third driving plate 503.  In other words, the radius of the
peripheral indention 5033 is slightly larger than the radius of the pressuring roller 40 so as to allow the pump tube 90 not being pressed within the guiding channel 12 when the pressuring roller 40 is located at the peripheral indention 5033. 
Accordingly, all five driving plates 501-505 have the same structure of the peripheral indentions.  The difference between the five driving plates 501-505 is the size of the pedal slot.  The arc length of the pedal slot 5035 of the third driving plate
503 is the same arc length of the pedal 33 such that the pedal 33 can be fitted into the pedal slot 5035 of the third driving plate 503.  In other words, the size and the shape of the pedal 33 of the transmission unit 30 is fitted right into pedal slot
5035 of the driving plate 503.  The third driving plate 503 is sandwiched between the identical second and fourth driving plates 502, 504, wherein the arc length of the pedal slot 5025, 5045 of each of the second and fourth driving plates 502, 504 is
larger than the arc length of the pedal slot 5035 of the third driving plate 503.  Preferably, arc length of the pedal slot 5025, 5045 of each of the second and fourth driving plates 502, 504 is additional 40.degree.  of the arc length of the pedal slot
5035 of the third driving plate 503.  In other words, the arc length of the pedal slot 5025, 5045 of each of the second and fourth driving plates 502, 504 is additional 40.degree.  extending at the operation direction, i.e. the rotational direction of
each of the second and fourth driving plates 502, 504.  The second, third, and fourth driving plates 502, 503, 504 are sandwiched between the identical first and fifth driving plates 501, 505.  In other words, the first and fifth driving plates 501, 505
are the two outer plates.  The arc length of the pedal slot 5015, 5055 of each of the first and fifth driving plates 501, 505 is larger than the arc length of the pedal slot 5025, 5045 of each of the second and fourth driving plates 502, 504. 
Preferably, arc length of the pedal slot 5015, 5055 of each of the first and fifth driving plates 501, 505 is additional 80.degree.  of the arc length of the pedal slot 5035 of the third driving plate 503.  In other words, the arc length of the pedal
slot 5015, 5055 of each of the first and fifth driving plates 501, 505 is 80.degree.  extending at the operation direction, i.e. the rotational direction of each of the first and fifth driving plates 501, 505.


The transmission unit 30 is connected to the driving shaft 20.  The driving plates 501-505 are overlappedly combined together to engage with the transmission unit 30 that the pedal slots 5015, 5025, 5035, 5045, and 5055 are coaxially aligned with
each other.  The pedal 33 of the driving element engages the pedal slots 5015, 5025, 5035, 5045, 5055 of the driving plates 501-505 such that when the driving element is driven to rotate by the driving shaft 20, the driving plates 501-505 are driven to
rotate subsequently by the pedal 33.


The peripheral indentions as shown in FIG. 3 all have sharp corners.  FIG. 4 illustrates an alternative mode of the peripheral indention wherein a corner of the peripheral indention 5033 of the third driving plate 503 can be modified as a round
corner as shown by the dotted line which tangents out with the outer diameter of the driving plate 503.  The second and third driving plates 502 504 can follow the same modification as the third driving plate 503 to minimize the clearance of the driving
plates 501-505 when the peripheral indentions of the driving plates 501-505 are misaligned to form an arc surface.  This modification does not affect the operation of the invention.  All driving plates 501-505 have the same thickness which their combined
thickness is equal to the width of the pressuring roller 40 and is approximately equal to two times of the width of the pressured pump tube 90.


The pressuring roller 40 has a diameter of approximately 2.5-3 times of the depth of the pump tube 90 needed to be compressed.  A width of the pressure roller 40 is approximately two times of the width of the compressed pump tube 90.  A retainer
shaft 44 protrudes out from two sides of the pressuring roller 40 and engages within a retainer slot 66 of the retainer 60 so that the pressuring roller 40 can be supported firmly and its distance between the pump tube 90 and the driving plates 501-505
can be retained.


According to the preferred embodiment of the present invention, the retainer 60 also helps to keep a predetermined distance between the pressuring rollers 40 but it does not affect the rotation and radial movement of them.  Accordingly, a movable
connecting rod can be installed in between the pressuring roller 40 and the retainer 60.  A central axis of both sides of the pressuring roller 40 can be connected to an end of the connecting rod.  This structural configuration does not affect the
operation of the invention also.


The outer casing 10 has the guiding channel 12 formed along the inner side of the peripheral wall of the outer casing 10 and defines the circular path therealong.  According to the preferred embodiment of the present invention, the pump tube 90
is installed in a full spiral manner in the guiding channel 12 of the outer casing 10.  An installation space is required for inserting the pump tube 90 into the guiding channel 12 of the outer casing 10.  In other words, a width of the guiding channel
12 is approximately about two times the width of the compressed pump tube 90 when the pump tube 90 is pressed by the pressuring roller 40 along the guiding channel 12.  Furthermore, the pump tube 90 is tangentially extended into the outer casing 10 at an
entrance of the guiding channel 12 until the operating portion of the pump tube 90 is received along the circular path of the guiding channel 12.  In addition, the operating portion of the pump tube 90 is retained in an arc shape within the guiding
channel 12 while the guiding portion of the pump tube 90, i.e. extending from the operating portion thereof, is tangentially extended with respect to the outer casing 10.  Therefore, the configuration of the pump tube 90 with respect to the outer casing
10 allows the liquid to flow in a maximized circular distance with respect to the circumference of the outer casing 10 such that when the pressuring rollers 40 substantially press against the pump tube 90, the liquid is forced to flow along the
arc-shaped operating portion of the pump tube 90 within the circular path at 120.degree.  so as to cancel the pulsation of the liquid within the pump tube 90.


If the peripheral wall of the outer casing 10 is too slippery, then the pump tube 90 might have a slight movement along the guiding channel 12 while in operation.  A plate can be installed at an entrance or exit location of the pump tube 90 in
the peripheral wall to limit the slight movement of the pump tube 90 along the guiding channel 12.  As an alternative, the peripheral wall of the guiding channel 12 can be formed as a rough surface to enhance the friction of the pump tube 90 against the
peripheral wall so as to avoid the movement along the guiding channel 12.


The operation principle of the present invention is explained below in detail:


In a release state when the driving shaft 20 is not rotating, the peripheral indentions of the all driving plates 501-505 are all aligned to each other so that a full arc indention surface is formed at the peripheral side of the combined driving
plates 501-505.  The pressuring roller 40 can then be fitted to engage the peripheral indentions of the driving plates 501-505 at a position that the circumferential surface of the pressuring roller 40 is engaged with the indention surface of the driving
plates 501-505.  The pump tube 90 can be installed now and there will not be any pressure exerted onto the operating portion of the pump tube 90.  When the driving shaft 20 starts to rotate in the operating direction, it will drive the transmission unit
30 to rotate as well.  The pedal 33 of the driving element of the transmission unit 30 will first engage the pedal slot 5035 of the driving plate 503 because the pedal slot 5035 is the narrowest out of the five driving plates 501-505 and thus drive the
driving plate 503 to rotate in the operating direction as well.  Once this motion starts, the peripheral indentions 5033 of the driving plates 501-505 will not be aligned to each other forming a full arc shape and thus disengage the peripheral indentions
of the driving plates 501-505 from the pressuring roller 40.  At this point, the pressuring roller 40 is then forced to radially extend towards the peripheral wall of the outer casing 10 and thus exerts a pressure on the pump tube 90.  When the driving
shaft 20 reaches a 40.degree.  rotation in the operating direction, the pedal 33 of the driving element of the transmission unit 30 will then engage the pedal slots 5025, 5045 of the second and fourth driving plates 502, 504 and thus drive the second and
fourth driving plates 502, 504 to rotate.  When the driving shaft 20 rotates an extra 40.degree.  in the operating direction, the pedal 33 of the driving element of the transmission unit 30 will then engage the pedal slots 5015, 5055 of the first and
fifth driving plates 501, 505 and thus drive the first and fifth driving plates 501, 505 to rotate.  At this moment, the peripheral indentions of each of the driving plates 501-505 will not be aligned and thus no indention or arc will be formed from the
combined driving plate 501-505.  Therefore, as long as the driving shaft 20 keeps rotating in the operating direction or does not rotating in a reverse direction until a predetermined degree of rotation, the peripheral indentions of the driving plates
501-505 will never be aligned with each other, thus the pressuring roller 40 will always be exerting pressure onto the operating portion of the pump tube 90.  Following the procedure above, the fluid in the pump tube 90 will be forced to be pumped thus
fulfilling to role of the peristaltic pump.  When the machine is not in use, rotate the driving shaft 20 in the reverse direction less than 180.degree.  and the peripheral indentions of the driving plates 501-505 will be aligned on top with each other
again.  Since the pump tube 90 itself is flexible and elastic in it self-nature, it will push back onto the pressuring roller 40 and thus forcing the pressuring roller to engage the aligned peripheral indentions of the driving plates 501-505 and the
present invention to return to the release state.


Referring to FIG. 2 of the drawings, the outer casing 10 further comprises an opening cover 80 which can be opened so as to make ease for the removal of the pump tube 90 and the center driving mechanism for repairing and such.


Referring to FIG. 5 and FIG. 6 of the drawings, using the same principle for operating the present invention, multiple pump tubes 90 can be used in the present invention.  The pump tubes 90 can be installed inside the guiding channel 12 of the
outer casing 10 in a similar manner as described above.  Multiple pump tubes 90 can be used as long as the pump tubes 90 are installed in a full circle manner around the peristaltic pump and have at least one of the pressuring rollers to be exerting
pressure on the operating portion of the pump tube 90.  FIG. 5 illustrates a configuration of the present invention using two pump tubes 90.  FIG. 6 illustrates a configuration of the present invention using three pump tubes 90.  Using the same principle
for operating the present invention, for example, a combined total number of 3 and 7 pieces of driving plates will also work in the same manner as described in the preferred embodiment as well as long as they are symmetrically installed on each sides of
the driving plate in the middle.  It is even possible to use only two driving plates to carry out the function of a five pieces driving plates 501-505 as described in the preferred embodiment.  Thus, the driving plates 501-505 of the transmission unit 30
are not limited by their numbers as long as an angle of the pedal slot of the driving plate correlates to a desired situation.


Referring to FIG. 7 of the drawings, an alternative of the driving plates 501-505 of the present invention is illustrated.  Using the driving plate 503 as example, the pedal slot 5035 can have a duplicated exact mirror feature of itself by
rotating 180.degree..  Therefore the pedal slot 5035 of the driving plate 503 is now double-sided.  A similar principle modification is applied to the pedal 33 of the driving element of the transmission unit 30 so as to increase the contact area between
the pedal 33 and pedal slot 5035 and thus creates a more stable and efficient rotation of the transmission unit 33.


Referring to the preferred embodiment of the present invention, the pressuring roller 40 and the drifting shaft 20 are made of metallic materials.  Other parts are made of plexiglass.  The peripheral wall of the guiding channel 12 of the outer
casing 10 is lathed in a single cut from a two layer plexiglass.  The entrance and exit location of the pump tube 90 can be milled from a milling machine and then the opening cover 80 of the outer casing 10 can be installed firmly thereon by screws.


Referring to FIG. 8 of the drawings, the present invention can also be produced in mass production by a casting of industrial plastic and similar materials.  The outer casing 10 can be split into an upper housing 17 and a lower housing 18.  In
between the upper housing 17 and lower housing 18, an edge 15 is defined at a joint area so that the upper housing 17 can be fittedly received inside the lower housing 18 and screws can be used to joint them.  Since multiple pump tubes 90 or different
brand or material of pump tubes 90 can be used in the present invention, the flexible pump tube 90 can reflect a different pressure back on the pressuring roller 40.  The upper housing 17 and the lower housing 18 can now rotate concentrically in an
independent manner so as to offer an option for tuning the angles or a routing route of installing pump tubes 90 into the guiding channel 12 of the outer casing 10.


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DOCUMENT INFO
Description: BACKGROUND OF THE PRESENT INVENTION1. Field of InventionThe present invention relates to a pump for propelling liquid through a flexible tube segment, and more particularly to a peristaltic pump for propelling liquid through the flexible tube in a concealed manner to ensure the purity of the liquidduring transmission and to prevent an environmental pollution of the peristaltic pump.2. Description of Related ArtsThe peristaltic pump is commonly used as a safe and stable liquid pumping device in many different fields such as the medical, pharmaceutical, chemical, nuclear, aviation, and environmental industries.Nowadays, conventional peristaltic pumps usually comprise an outer casing, a flexible pump tube which is adapted for allowing fluid to flow therealong, a plurality of rotating rollers spacedly supported at the outer casing at equal radialdistance. The rotating rollers exert pressure on the pump tube thus to propel the liquid. A negative pressure will then be formed when the pump tube returns to it normal position so ask to suck in fluid from the source and thus continuously propel thefluid to travel in the pump tube. There are many disadvantages for such a conventional peristaltic pump. For examples, the peristaltic pump enclosed in China Patent CN85204827 and CN87107936 uses the rotating rollers to only exert pressure on the pumptube in a particular arc section of the guiding channel so as to achieve a more convenient installation of the pump tube. As a result, the design will experience a radial pulsing force on a particular section of the pump tube and also faces thefollowing problems that are hard to overcome:1. a high power motor is required to drive the machine to overcome the friction on the particular side, especially for the initial force and the torque, therefore it increases the size of the machine, i.e. the bigger size of driving shaft andthe power of the motor, and the design has a low efficiency;2. the machine is easy to wear out, a specia